Gate roller duster - GIF

[ductape]

This doesn't make any sense to me.
Is the intention to clean the car? The rolls are turning so they are not wiping much dust off, and it seems it might even scratch the paint.
Is this a self opening/closing gate, so he doesn't have to get out of the car? There is nothing obvious that would keep either the bad guys or the cows from going right through.

Can anybody help me understand?

It's an attempt to prevent damage to a vehicle driving through the gate. Not especially good at it, but fairly common in some areas. This one is in China.